Contact for vibrators



Maid! 18,4 '1941. F. sci-nl GEN- Erm. 2,235,171

CONTACT FOR VIBRATORS Filed arch 24, 1939 f INVENTORS Fmz Schi/gen ATTORNEY.

lPatented Mar. 18,l 11941 UNITED STATES PATENT OFFICE CONTACT FOR VIBRATORS Germany Application March 24, 1939, Serial No. 263,966 In Germany March 24, 1938 4 claims. y(c1. zoo- 166) ing contacts are pressed together. The advan-` tage of such an arrangement is that the friction and therefore the loss of Jenergy of the vibrating ,reed is small. Further the contact l opens and closes very quickly, because the motion is directed perpendicular to the contact surface. .Thereby the sparks (or arcs) at the closing and opening are diminished'. i A disadvantage of such a device is that the two contact pieces touch each other at only a few points of their surfaces for the reason that the contact surfacesv with no or little friction existing are not sliding over each other. This causes the transmission resistance of the con- '20 tact to be quite large and to increase during the working period. 'I'he large transmission resistance causes the contact to become very hot especially for large currents,l thus appreciabiy decreasing the life of the contacts. It is also a fact that with such device pin-formation (that is, travel of material) is accelerated whereby a pin-like excrescence arises almost -at the cathode and a considerably deepcrater is formed at the anode. In the operation of the device under such conditions, the crater usually destroys the anodic contact piece very rapidly.n

Itis known to form a contact so that a substantially frictional contact touching arises.-f The transmission resistance of such contact is small since the pieces slide over each other and clean themselves automatically. But in-\"`such cases the loss of energy and material is `very large. Also the sparks or Aarcs at the closing and opening are very large,..,because the -motion as o the contact touches is directed tangential to the contact surfaces and therefore the opening and closing is very slow. As the result of this such formed contacts have not vbeen employed heretofore at vibrators.

45 It is a main object of the present invention to avoid these disadvantages by forming and arranging the contact in that manner-such a substantially pressing contact results at one place and a substantially frictional contact at another 50 place. I, f

' The present invention combines the advantages of both the pressing and the frictional'contact devices without their disadvantages. The pressing part of the contact effects the rapid 55 closing and opening of the contact. The frictional part of the contact is conducting the largest part of the current during the largest part of the time that the contact is closed. Therefore the pressing part is unburdened and is prevented from becoming hot. As the press ing part of the contact wears slowly and its transmission resistance increasesythe other part acts to conduct more and more of the current. In this way the life of the contacts is considerably increased. 1G

The advantages above set forth are effective preferably if the contact is formed and arranged in such a manner that while it is being closed the pressing contact'arises first and the frictional contact secondly, while when the contact l5 is being opened the two contact places are severed in the reverse succession. Thus the pressing part closes at flrst with little sparking because of the high velocity of closing and thereafter the frictional part closes without a 20 spark since the other part has already closed and no voltage exists between the two contact pieces of the frictional part of the contact. At opening of the contact, sparking is avoided by sevu ering the sliding part before the pressing part, 25 the latter being opened a short time after the sliding part has been opened.

The invention is illustrated in reference to the accompanying drawing, of which Fig. 1 shows an embodiment of the invention 30 in the open position diagrammatically,

Fig. 2 shows the same embodiment in the 1 close position,

Fig. 3 shows another embodiment of the in-1 vention.

In Fig. 1 the vibrating reed F of a mechanical interrupter which is shown in cross-section perpendicular to the direction of the reed, carries a pin-like contact piece K1, which is consisting of carbon at least at its conical front part K. This front part carries a little plate K1, consisting of a hardmetal (for instance Wolfram). The countercontact-piece is a little plate consisting also of Wolfram which is carried by the U-like blade-spring Kx. This spring is consisting of copper or another metal which is not too hard and is fastened on the counter-plate G by supports B1 and Bz.

While Fig. 1 shows the arrangemlent in the normal position inwhich the contact is opened, Fig. 2 shows the same'arrangement in that positlon in which the reed F is bent off to below and closes the contact. At the motion to below the passing contact pieces Ki' and Kn' touch each other. Therefore the elastic spring K2 is pressed 55 down and is strained simultaneously so that the U-like formed part is stretched and is contracted at its mouth. As the result of this the mouth places S1 and Sz of the spring Ks touch frictionally the side surfaces of the cone K4 consisting of carbon. Now a considerable part of the current is owing through the frictional contact part. 'Ihe contact parts open inthe adverse succession.

After a large work-time of the interrupter if the pressing contact pieces consisting of wolfram are worn out, the contact pin K1 engages more deep into the U-like formed aperture of the counter-contact spring K2. Therefore the percentage portion of the frictional contact par at the conducting of current increases.

The counterplate G can be rigid, if the spring K2 is elastic sufliciently. Furthermore a vibrating lever instead of a vibrating reed may be controlling the contact pin K1.

Fig. 3 is showing another embodiment of the invention, which is similar to the embodiment shown in Fig. 1 and Fig. 2, but diers in that the moved contact pin K1 is supplied with a groove R in which the side-walls of the counterpiece Kn are able to snap in, so that the pin-is arrested during a large portion of thetime in which the contact is closed. -Thereby avery large velocity of opening is obtainable. What we claim is:

1. In a vibrating interrupter, a make and break switch adapted to be operated at high speeds, said switch comprising a vibrating pinlike element forming one electrode thereof and a substantially xedly mounted spring-cradle element forming the cooperating electrode ofthe switch, said two elements being positioned with respect to each other so that one end of the pinlike clement operates within the spring-cradle, the range of movement of the pin-like element being sufficient so that in one direction of oppin-like element and in the other direction to completely break contact with the spring-cradle.

2. The arrangement described in the next pre-I portion of the spring-cradle with which said end comes in contact are made of comparatively hard conductive material to withstand wear whereas the portions of said elements which come in sliding contact are made of material having high electrical conductivity.

3. In a vibrating interrupter provided with a make and break switch adapted to be operated at high speeds, said switch comprising a. vibrating pin-like element forming one electrode of the switch and a` substantiallyv flxedly mounted spring-cradleyelement forming the cooperating electrode, said two-elements being positioned with respect to each other so that in the operation of the interrupter one end of the pin-like element makes and breaks contact with a portion of the inner side of the base of the spring-cradle, the range of movement of said pin-like element being suiiicient in Onedirection to tension the cradle sufficiently so as to cause its sides to come in sliding contact -with the outer surface of the pin-like element on make and in the other direction to move completely free from the cra*- dle whereby on make a substantially xed pressure contact is iirst established between a portion of the cradle element and a portion of the pin-like contact element and thereafter a sliding contact is established between different portions of said elements and on break said sliding contact is rst broken after which said pressure contact is broken.

4. In a vibrating interrupter provided with a make and break switch adapted to bek operated at high speeds, said switch having one contact element formed as a pin-like structure and a cooperating contact element formed as a springcradle, a contact piece mounted within the spring-cradle and positioned so as to contact one end of the pin-like element and thereby establish contact between said two elements on make, said two contact elements being arranged so that the pin-like contact elementis moved toward said contact piece to make contact between said elements and away from the contactpiece to break contact between said elements, the pin-` like -element being arranged to continue its movement in thedirection of -make for a predetermined distance after contact is establishedV between said end thereof and the contact element, said continued motion acting upon the spring-cradle to bring the sides thereof in slid-' ceding claim; wherein the end of the pin-like "tact piece and thereafter a sliding cqntact '1S element which makes said first contact andtl'i'ta" established between a-portion of the spring cradle and the pin-like'element, and on break thev sliding contact is rst broken after which-said substantially fixed contact is broken.

ALFRED LEIFER. FRITZ SCHILGEN. 

